Do you print ABS with the fan on, or off?
Hey all,
I'd like to take a poll of those who are able to consistently print good parts out of ABS. I've had serious problems with my parts melting while printing. Adding a minimum layer time (gone up to 1 min per layer), slowing the print speed (down to 25 mm/s), printing multiples, none of these things worked. The only thing that has helped has been boosting the extrusion temperature and turning the fan on. Numerous people have insisted that the fan must be off to print ABS... which makes sense. One wants the plastic to solidify slowly. I'm just curious how many people have run into the problem I have and now produce good ABS prints with the fan on.
Best,
E
Re: Do you print ABS with the fan on, or off?
In general ABS is being printed with fan off. But this is not a binary decision. If fan helps to succeed with a print, it will be used for exactly those needed layers.
Often linked posts:
Going small with MMU2
Real Multi Material
My prints on Instagram
Re: Do you print ABS with the fan on, or off?
I more or less can't get away without it, and I've read reports of people having the same experience. Perhaps I should just continue dropping the temperature?
Re: Do you print ABS with the fan on, or off?
It highly depends on the objects you print. If you print mostly stuff where you have overhangs and/or very short time per layer, you will need to turn the fan on for this layers.
Beside of that I wouldn't recommend to drop the temp. It's better to print hot with fan on.
Often linked posts:
Going small with MMU2
Real Multi Material
My prints on Instagram
Re: Do you print ABS with the fan on, or off?
Numerous people have insisted that the fan must be off to print ABS... which makes sense. One wants the plastic to solidify slowly.
It's also possible that "numerous people" are just repeating things they've heard that sound nice, without putting much thought into the matter.
I think the "fan off for ABS" is a fairly old idiom from when printers weren't commonly enclosed, hotends would not be able to get that hot and blasting cold air across a print was "cooling".
These days we have a lot more control, and in an enclosure you should be able to cool using a pretty high ambient temperature. There is little reason not to run a fan.
The main concern with ABS (and PC and other high shrink materials) is that they shrink as they cool. However, the correct control to handle shrinkage during a print is the ambient temp in an enclosure. Not the fan. Prints usually run for several hours. The majority of the print is going to sit at ambient temp, with the appropriate amount of shrinkage for that time. The tiny bit of the print that the fan has just cooled from above to below melt point isn't going to have much of an effect on that shrinkage. It will however, mean that tiny bit of detail you just printed is not drooping/warped.
Also, a dead giveaway as to the effectiveness of a cooling fan is to look at printers that are optimised for ABS. eg: Zortrax M200 - cooling fan - yep.